| SHAO Yan-fan,WANG Ze-hua,LI Xiao,LI Jin-long,GU Chen-yu.Microstructure and Properties of Laser Cladding Co-based Alloys on Duplex Stainless Steel[J],49(4):299-305 |
| Microstructure and Properties of Laser Cladding Co-based Alloys on Duplex Stainless Steel |
| Received:May 21, 2019 Revised:April 20, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2020.04.035 |
| KeyWord:laser cladding duplex stainless steel Co-based alloys wear resistance corrosion resistance |
| Author | Institution |
| SHAO Yan-fan |
1.College of Mechanics and Materials, Hohai University, Nanjing , China |
| WANG Ze-hua |
1.College of Mechanics and Materials, Hohai University, Nanjing , China |
| LI Xiao |
1.College of Mechanics and Materials, Hohai University, Nanjing , China |
| LI Jin-long |
2.Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo , China |
| GU Chen-yu |
1.College of Mechanics and Materials, Hohai University, Nanjing , China |
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| Abstract: |
| The paper aims to improve the wear resistance and corrosion resistance of 2205 duplex stainless steel. A cobalt-based alloy coating was prepared on 2205 duplex stainless-steel substrate by laser cladding technology. The phase composition and microstructure of the cobalt-based alloy coating were analyzed with X-ray diffractometer and optical microscope. The element distribution of Fe and Cr in the coating and substrate interface was detected with energy spectrometer, and the width of the transition region was determined. The hardness and abrasive resistance of the coating were tested with microhardness tester and wet sand abrasive wear tester. The wear characteristics of the friction surface were observed under scanning electron microscopy. The wear mechanism of the cobalt-based alloy coating was analyzed. The electrochemical corrosion characteristics of the coating were tested with electrochemical workstation. The comparing tests were conducted to 2205 duplex stainless steel. The coating consisted of γ-Co solid solution and a small amount of Cr7C3, Cr2Ni3 phases. The microstructure of the coating at the interface was composed of cell crystals and a small amount of planar crystals and other regions were of dendrites. Since the coating was formed by multiple layers of cladding, the dendrites of the coating grew in different directions. The transition zone of the coating was very narrow, which was about 50 μm, and the average microhardness of the coating was 477HV0.1, which was far higher than that of 2205 duplex stainless steel matrix. When the wear distance reached 3354 m, the mass loss of the coating was only 10.3 mg, about one third of the mass loss of 2205 duplex stainless steel. In a 3.5% NaCl solution, the coating had a higher polarization resistance and charge transfer resistance and a lower self-corrosion current. The coating is dense, free from pore, crack and other defects, and bonded with the substrate properly. The cobalt-based alloy coating has a much better wear resistance and corrosion resistance. |
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